1. Technical Field
The present invention generally relates to a backlight module and, more particularly to a backlight module having an integrated optical film.
2. Description of the Related Art
FIG. 1 is a schematic side view of a conventional backlight module. Referring to FIG. 1, the backlight module 100 includes a light source 110, a diffusion plate 120, a first diffusion film 130 and a second diffusion film 140. The light source 110 includes a box 112 and a plurality of light tubes 114 disposed in the box 112. The diffusion plate 120 is disposed on the light source 110. The first diffusion film 130 and the second diffusion film 140 are disposed on the diffusion plate 120 in proper order. The brightness of the backlight module 100 generally is low and about 9528 candelas per square meter (cd/m2).
In order to overcome the above-mentioned problem of insufficient brightness, several improving methods are provided as described below. FIG. 2 is a schematic side view of another conventional backlight module. Referring to FIG. 2, the difference between a backlight module 200 and the backlight module 100 is that the backlight module 200 further includes a third diffusion film 250. The brightness of the backlight module 200 is about 9687 cd/m2. However, the brightness of the backlight module 200 is still not sufficient enough. FIG. 3 is a schematic side view of another conventional backlight module. Referring to FIG. 3, the difference between a backlight module 300 and the backlight module 100 is that the backlight module 300 is equipped with two pieces of microlens films 310 and 320 instead of the first diffusion film 130 and the second diffusion film 140 of the backlight module 100. The brightness of the backlight module 300 is about 9736 cd/m2. However, the brightness of the backlight module 300 is still insufficient.
FIG. 4 is a schematic side view of another conventional backlight module. Referring to FIG. 4, the difference between a backlight module 400 and the backlight module 100 is that a prism sheet 450 is disposed between a first diffusion film 430 and a second diffusion film 440. Accordingly, the brightness of the backlight module 400 is effectively improved. However, the number and kind of elements of the backlight module 400 are excessive such that the cost of assembling the backlight module 400 is high.